drivers/gpu/drm/vc4/vc4_kms.c

   1 /*
   2  * Copyright (C) 2015 Broadcom
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 /**
  10  * DOC: VC4 KMS
  11  *
  12  * This is the general code for implementing KMS mode setting that
  13  * doesn't clearly associate with any of the other objects (plane,
  14  * crtc, HDMI encoder).
  15  */
  16
  17 #include "drm_crtc.h"
  18 #include "drm_atomic.h"
  19 #include "drm_atomic_helper.h"
  20 #include "drm_crtc_helper.h"
  21 #include "drm_plane_helper.h"
  22 #include "drm_fb_cma_helper.h"
  23 #include "vc4_drv.h"
  24
  25 static void vc4_output_poll_changed(struct drm_device *dev)
  26 {
  27         struct vc4_dev *vc4 = to_vc4_dev(dev);
  28
  29         drm_fbdev_cma_hotplug_event(vc4->fbdev);
  30 }
  31
  32 struct vc4_commit {
  33         struct drm_device *dev;
  34         struct drm_atomic_state *state;
  35         struct vc4_seqno_cb cb;
  36 };
  37
  38 static void
  39 vc4_atomic_complete_commit(struct vc4_commit *c)
  40 {
  41         struct drm_atomic_state *state = c->state;
  42         struct drm_device *dev = state->dev;
  43         struct vc4_dev *vc4 = to_vc4_dev(dev);
  44
  45         drm_atomic_helper_commit_modeset_disables(dev, state);
  46
  47         drm_atomic_helper_commit_planes(dev, state, 0);
  48
  49         drm_atomic_helper_commit_modeset_enables(dev, state);
  50
  51         /* Make sure that drm_atomic_helper_wait_for_vblanks()
  52          * actually waits for vblank.  If we're doing a full atomic
  53          * modeset (as opposed to a vc4_update_plane() short circuit),
  54          * then we need to wait for scanout to be done with our
  55          * display lists before we free it and potentially reallocate
  56          * and overwrite the dlist memory with a new modeset.
  57          */
  58         state->legacy_cursor_update = false;
  59
  60         drm_atomic_helper_wait_for_vblanks(dev, state);
  61
  62         drm_atomic_helper_cleanup_planes(dev, state);
  63
  64         drm_atomic_state_free(state);
  65
  66         up(&vc4->async_modeset);
  67
  68         kfree(c);
  69 }
  70
  71 static void
  72 vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb)
  73 {
  74         struct vc4_commit *c = container_of(cb, struct vc4_commit, cb);
  75
  76         vc4_atomic_complete_commit(c);
  77 }
  78
  79 static struct vc4_commit *commit_init(struct drm_atomic_state *state)
  80 {
  81         struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
  82
  83         if (!c)
  84                 return NULL;
  85         c->dev = state->dev;
  86         c->state = state;
  87
  88         return c;
  89 }
  90
  91 /**
  92  * vc4_atomic_commit - commit validated state object
  93  * @dev: DRM device
  94  * @state: the driver state object
  95  * @nonblock: nonblocking commit
  96  *
  97  * This function commits a with drm_atomic_helper_check() pre-validated state
  98  * object. This can still fail when e.g. the framebuffer reservation fails. For
  99  * now this doesn't implement asynchronous commits.
 100  *
 101  * RETURNS
 102  * Zero for success or -errno.
 103  */
 104 static int vc4_atomic_commit(struct drm_device *dev,
 105                              struct drm_atomic_state *state,
 106                              bool nonblock)
 107 {
 108         struct vc4_dev *vc4 = to_vc4_dev(dev);
 109         int ret;
 110         int i;
 111         uint64_t wait_seqno = 0;
 112         struct vc4_commit *c;
 113         struct drm_plane *plane;
 114         struct drm_plane_state *new_state;
 115
 116         c = commit_init(state);
 117         if (!c)
 118                 return -ENOMEM;
 119
 120         /* Make sure that any outstanding modesets have finished. */
 121         if (nonblock) {
 122                 struct drm_crtc *crtc;
 123                 struct drm_crtc_state *crtc_state;
 124                 unsigned long flags;
 125                 bool busy = false;
 126
 127                 /*
 128                  * If there's an undispatched event to send then we're
 129                  * obviously still busy.  If there isn't, then we can
 130                  * unconditionally wait for the semaphore because it
 131                  * shouldn't be contended (for long).
 132                  *
 133                  * This is to prevent a race where queuing a new flip
 134                  * from userspace immediately on receipt of an event
 135                  * beats our clean-up and returns EBUSY.
 136                  */
 137                 spin_lock_irqsave(&dev->event_lock, flags);
 138                 for_each_crtc_in_state(state, crtc, crtc_state, i)
 139                         busy |= vc4_event_pending(crtc);
 140                 spin_unlock_irqrestore(&dev->event_lock, flags);
 141                 if (busy) {
 142                         kfree(c);
 143                         return -EBUSY;
 144                 }
 145         }
 146         ret = down_interruptible(&vc4->async_modeset);
 147         if (ret) {
 148                 kfree(c);
 149                 return ret;
 150         }
 151
 152         ret = drm_atomic_helper_prepare_planes(dev, state);
 153         if (ret) {
 154                 kfree(c);
 155                 up(&vc4->async_modeset);
 156                 return ret;
 157         }
 158
 159         for_each_plane_in_state(state, plane, new_state, i) {
 160                 if ((plane->state->fb != new_state->fb) && new_state->fb) {
 161                         struct drm_gem_cma_object *cma_bo =
 162                                 drm_fb_cma_get_gem_obj(new_state->fb, 0);
 163                         struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
 164
 165                         wait_seqno = max(bo->seqno, wait_seqno);
 166                 }
 167         }
 168
 169         /*
 170          * This is the point of no return - everything below never fails except
 171          * when the hw goes bonghits. Which means we can commit the new state on
 172          * the software side now.
 173          */
 174
 175         drm_atomic_helper_swap_state(state, true);
 176
 177         /*
 178          * Everything below can be run asynchronously without the need to grab
 179          * any modeset locks at all under one condition: It must be guaranteed
 180          * that the asynchronous work has either been cancelled (if the driver
 181          * supports it, which at least requires that the framebuffers get
 182          * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
 183          * before the new state gets committed on the software side with
 184          * drm_atomic_helper_swap_state().
 185          *
 186          * This scheme allows new atomic state updates to be prepared and
 187          * checked in parallel to the asynchronous completion of the previous
 188          * update. Which is important since compositors need to figure out the
 189          * composition of the next frame right after having submitted the
 190          * current layout.
 191          */
 192
 193         if (nonblock) {
 194                 vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
 195                                    vc4_atomic_complete_commit_seqno_cb);
 196         } else {
 197                 vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false);
 198                 vc4_atomic_complete_commit(c);
 199         }
 200
 201         return 0;
 202 }
 203
 204 static const struct drm_mode_config_funcs vc4_mode_funcs = {
 205         .output_poll_changed = vc4_output_poll_changed,
 206         .atomic_check = drm_atomic_helper_check,
 207         .atomic_commit = vc4_atomic_commit,
 208         .fb_create = drm_fb_cma_create,
 209 };
 210
 211 int vc4_kms_load(struct drm_device *dev)
 212 {
 213         struct vc4_dev *vc4 = to_vc4_dev(dev);
 214         int ret;
 215
 216         sema_init(&vc4->async_modeset, 1);
 217
 218         ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
 219         if (ret < 0) {
 220                 dev_err(dev->dev, "failed to initialize vblank\n");
 221                 return ret;
 222         }
 223
 224         dev->mode_config.max_width = 2048;
 225         dev->mode_config.max_height = 2048;
 226         dev->mode_config.funcs = &vc4_mode_funcs;
 227         dev->mode_config.preferred_depth = 24;
 228         dev->mode_config.async_page_flip = true;
 229
 230         drm_mode_config_reset(dev);
 231
 232         vc4->fbdev = drm_fbdev_cma_init(dev, 32,
 233                                         dev->mode_config.num_crtc,
 234                                         dev->mode_config.num_connector);
 235         if (IS_ERR(vc4->fbdev))
 236                 vc4->fbdev = NULL;
 237
 238         drm_kms_helper_poll_init(dev);
 239
 240         return 0;
 241 }